Looking to install a runtime hook when the program...

# kotlin-native

[Matt Nelson]

Looking to install a runtime hook when the program completes for Kotlin/Native (kind of like Jvm's File.deleteOnExit()). Anyone know of a K/N API that I can use to build off of that would provide similar functionality?

[jw]

For POSIX https://linux.die.net/man/3/atexit

[jw]

You'd still need to install signal handlers if you want to run code on interrupts that normally terminate the process

[jw]

Maybe you could try https://github.com/JakeWharton/finalization-hook/ though

[Matt Nelson]

Thanks Jake!

[Adam S]

AutofreeScope has defer {}, for when the memory scope is finished, which is similar

https://kotlinlang.org/api/core/kotlin-stdlib/kotlinx.cinterop/-autofree-scope/#-2026372596%2FFunctions%2F1938390331

[jw]

True, although that's basically sugar over a list of lambdas which are run as part of a try/finally as a mechanism of execution so you won't run if signaled, but maybe that's okay.

https://github.com/JetBrains/kotlin/blob/7b127d84dca7bb7527f8caf94abbf121c81cd3ce/kotlin-native/Interop/Runtime/src/main/kotlin/kotlinx/cinterop/Utils.kt#L717-L721

https://github.com/JetBrains/kotlin/blob/7b127d84dca7bb7527f8caf94abbf121c81cd3ce/kotlin-native/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/cgen/CBridgeGenUtils.kt#L241-L244

[Matt Nelson]

I thought about that, but unfortunately will not work for my use case. Trying to get the same/similar functionality as File.deleteOnExit() where the hook executes when the VM shuts down. Looking into using signal handlers atm.

[Matt Nelson]

Wait, jake... finalization-hook is a suspend function, so I could do something like?

GlobalScope.launch {
  withFinalizationHook(
    hook = ::executeDeleteOnExit,
    block = { delay(Duration.INFINITE) }
  )
}

[jw]

Probably? Although it's not set up for you to do that more than once, but it would be possible to add that

[Matt Nelson]

Yeah, unfortunately it wasn't working when I was playing around with things.

I purposefully caused a segmentation fault which re-sends SIGABRT, but it wasn't catching it. Ended up just using sigaction for Unix which is working. Still have to figure out Windows.

nativeMain
https://github.com/05nelsonm/kmp-tor-resource/blob/master/library/resource-noexec-tor/src/nativeMain/kotlin/io/matthewnelson/kmp/tor/resource/noexec/tor/internal/DeleteOnExit.kt

unixMain
https://github.com/05nelsonm/kmp-tor-resource/blob/master/library/resource-noexec-[…]nelson/kmp/tor/resource/noexec/tor/internal/DeleteOnExitUnix.kt